An example of a conventional service expanding system is described in a literary document of a lecture on Nov. 15, 1999 “Application Front-end and the Management Middleware Thereof” by Tomohiro Ijikakura, Tohru Egashira, and yoshiaki Kiriha: Study Group for Telecommunication Management (TM) in Academic Conference of Electronics, Information and Communication.
A constitution of the above-described prior art will be described in detail by referring to a diagram.
FIG. 1 is a constitutional block diagram showing a service expanding system FM1, which has been heretofore applied.
The conventional service expanding system FM1 is composed of a look-up functional section 1202, a probe functional section 1203, a front-end control section 1204, a server control section 1205, and a communication base 1206. Furthermore, a client C1, a front-end F1, and a server S1 exist on the service expanding system FM1.
In this case, the client C1 means a program for receiving services that exist on computers, and it is provided by a server because of making a connection with the nearest communication device in a communication network composed of communication devices and computers. For instance, it is a Web browser in WWW (World Wide Web), or a mail reader in electronic mail service. In FIG. 1, although only one client exists, pluralities of clients exist on the service expanding system FM1 in reality.
Moreover, the server S1 corresponds to a program for providing any service that is implemented by an entrepreneur who gains profits from provision of a variety of services such as connection service with the communication network, Web service, and electronic mail, service with respect to customers by utilizing the above-described communication network (hereinafter referred to as simply “entrepreneur”). For example, it is an HTTP server-translating HTTP (hyper-text transfer protocol) in case of the above-mentioned WWW service. While only a single server exists in FIG. 1, a plurality of servers exists actually on the service expanding system FM1.
Besides, the front-end F1 is a light program implemented by an entrepreneur that stands in between the server S1 and the client C1, and which acts for execution of a part of data processing function of the server S1 on a communication device. In FIG. 1, although only a single front-end is in existence, pluralities of front-ends reside on the service expanding system FM1 in reality.
In the following, respective components of the service expanding system FM1 will be described.
The look-up functional section 1202 has a function for looking up a place of a front-end F1 capable of being connected from a name of service needed to use the same by a client C1. More specifically, a plurality of front-ends each providing the same service are grouped, and the optimum front-end (the front-end F1 in FIG. 1) for the client C1 is selected from the plurality of front-ends belonging to these groups in case of searching such front-ends. As manners for selecting the optimum front-end include, for example, one for selecting the nearest front-end from a client, one for selecting a front-end having the lowest load among those belonging to a certain group, one for selecting each of them belonging to a certain group in a sequential order, and the like.
The probe functional section 1203 that resides between the front-end F1 and the client C1 as occasion demands and has a function for acquiring a variety of statistical information produced between the front-end F1 and the client C1. The statistical information includes, for example, an amount of communication transmitted and received between the front-end F1 and the client C1, an amount of resources for communication device that was consumed by the front-end F1 within a certain period of time such as an amount of memory, and the like.
The front-end control section 1204 has a function for effecting communication of the front-end F1 with the server S1 by transmitting mutually each message between the front-end F1 and the server S1 (hereinafter referred to as “fundamental communicating function”), a function for controlling the front-end F1 as to, for example, production, deletion, stop and the like thereof, which is effected by a request for control by the undermentioned server control section 1205 or the front-end F1, and a function for transmitting a change of state such as abnormal termination of, for example, the front-end F1 to the server control section 1205.
The server control section 1205 has a function for administering a program including the front-end F1, the above-mentioned fundamental communicating function, a function for controlling, for example, production, extinguishment and the like of a group obtained by bundling front-ends each providing the same service (hereinafter referred to as “front-end group”), a function for processing statistical information collected by a plurality of the probe functional sections 1203, a function for transmitting a request for controlling a front-end such as production, and deletion of such front-end from the server S1 to the front-end control section 1204, and a function for transmitting a notification for a change of state of a front-end F1 transmitted from the front-end control section 1204.
The communication base 1206 has a function for realizing a communication among the look-up functional section 1202, the probe functional section 1203, the front-end control section 1204, and the server control section 1205 that have been mentioned above, respectively.
Furthermore, each component of the above-mentioned service expanding system FM1 affords functions contained in each of such components with respect to the client C1 as well as the front-end F1, and an interface that is made to be applicable by the server S1 (hereinafter referred to as “middleware functional interface”). This middleware functional interface is a programming interface by which it makes possible to construct an application such as a function in a programming language, for example, a method or the like in Java language, and a CORBA (common object request broker architecture) operation defined by IDL (interface definition language) in CORBA on the service expanding system FM1.
A first problem involved in the above-mentioned prior art resides in that it cannot be assured to provide an efficient service to a client that connected with a front-end. This is because when a front-end with which the client C1 should be connected is selected in the look-up functional section 1202, it is selectable from only existing front-ends as to front end groups, and in other words, the service expanding system FM1 does not have a function for distributing newly front-ends according to need.
A second problem is in an expensive cost for developing server. This is because the prior art adopts such policy that a control function of front-end such as distribution, deletion and the like is to be implemented to the server S1. Thus, the same control function of front-end must be implemented to each server in spite of a fact that control function of front end to be implemented in a server is the same throughout substantially whole service.
A third problem involved in the prior art resides in that an extravagant cost is required for administrating services. This is because the same control method is not necessarily adopted in all the servers according to an intention of a server developer in spite of the fact that control function of front end to be implemented in a server is the same throughout substantially whole service as mentioned above, so that an entrepreneur must master different manners for administration in each service, respectively.